1. Field of the Invention
The present invention is directed to debris and litter collecting machines of the type that are generally intended to cover relatively large areas over which debris may be scattered, such as parks, beaches, highways, etc., and to retrieve the debris or litter that is commonly encountered in these areas.
2. Description of Related Art
Various litter collecting machines of this general type are disclosed, for example, in U.S. Pat. Nos. 2,916,753; 3,923,101; 3,993,141; 4,550,465 and 4,593,426. Litter retrieval machines of this type basically comprise a device for picking litter up from the ground, a storage bin or hopper for receiving the litter that has been picked up, and some form of means for transferring the litter from the collecting device to the storage bin.
A device substantially similar to that disclosed in abandoned U.S. patent application Ser. No. 06/606,583 has been sold in the United States more than one year prior to the filing of this application.
In some of these machines, the transfer of the collected litter from the collector to the storage bin involves a number of discrete handling steps in which the litter goes from one location to another between the ground and the storage bin. However, each time that a piece of litter must be handled by a separate piece of structure in the machine provides an instance in which the overall collecting efficiency of the machine can be reduced. For example, when a transfer of litter between two relatively moving machine elements is required, it is always possible that flexible types of litter such as cardboard cartons or paper wrappers can become jammed between the two elements and, rather than being transferred from one to the other, be returned to the ground or require stoppage of the machine to clear the obstruction. In another type of action, collected litter may be allowed to freely drop from one type of handling apparatus into another. For example, it may fall from a collecting roller into a trap area where it is picked up by a subsequent handling device. In such situations, it is entirely possible that litter such as glass bottles or the like may break as it falls into the trap area, allowing the smaller pieces to drop through spaces in the machine and return to the ground.
Some litter collecting machines, such as those disclosed in the previously noted '101 and '141 patents, employ a relatively simple collecting concept that does not involve numerous handling steps in transferring the litter from the collecting device to the storage bin. However, the basic collecting device itself is also simple in concept, comprising a series of relatively rigid rods mounted on a shaft and adapted to picking up certain types of litter or litter of certain sizes that is capable of being wedged between the rods.
A further disadvantage of litter collecting machines that utilize a plurality of flexible fingers to collect litter, such as those disclosed in U.S. Pat. Nos. 4,550,465 and 4,593,426, is that the fingers are subject to wear, thus reducing their effectiveness. The fingers in the prior art machines are difficult to replace.